While many studies have focused on estimating a relationship between pollution and health, they have largely neglected to consider that pollution exposure is endogenously determined if individuals make choices to maximize their well-being. People with high preferences for clean air may choose to live in areas with better air quality. People can respond to a wide range of readily available information on pollution levels by adjusting their exposure. Failing to appropriately account for such actions can yield misleading estimates of the causal effect of pollution on health. .
